US20060249440A1 - Collapsible process tank for a water purification system - Google Patents

Abstract

The invention provides an apparatus having a tank having at least a portion of its surface collapsible such that the tank can be configured in either a deployed position or a smaller stored position. A membrane module is located in the tank. The tank has a feed inlet and a permeate port in communication with the membrane module. When in the deployed position, water enters the inlet and flows through the membrane and out the permeate port in a filtration process. When filtration is no longer required, the tank can be collapsed for transport. The membrane module may remain in the tank when the tank is collapsed.

Description

• This is an Application claiming the benefit under 35 USC 119(e) of U.S. Ser. Nos. 60/592,146 filed Jul. 30, 2004 and 60/613,222 filed Sep. 28, 2004. U.S. Ser. Nos. 60/592,146 and 60/613,222 are incorporated herein, in their entirety, by this reference to them.
FIELD OF THE INVENTION
• The invention relates to water purifications systems, and in particular, to a collapsible tank which may contain filtering membranes and be used for a water treatment system.
BACKGROUND OF THE INVENTION
• Numerous water purification systems are known. One known type of water purification systems are mobile or portable systems which are designed to be transportable from place to place by vehicles.
• One such portable system is disclosed in U.S. Pat. No. 6,120,688. The system disclosed includes a rigid tank which is made of material, such as stainless steel, aluminum, polyethylene or the like. The process tank and system disclosed in the patent have the disadvantage of requiring a large vehicle for transportation thereof. Typically, such a system requires a 5/4 ton or greater class of vehicle. In certain applications, such as the military, it is desirable to provide a water purification system and process tank which can be transported by a smaller vehicle, such as a HUMWV (High Mobility Multipurpose Wheeled Vehicle).
• Accordingly, there is a need for a process tank and a water purification system with improved portability, such as those which can transported by smaller vehicles.
SUMMARY OF THE INVENTION
• The following summary is intended to introduce the reader to the invention but not to define it. The invention may reside in any novel or inventive combination of apparatus elements or process steps found in any part of this document. An object of the invention is to improve on, or at least provide a useful alternative to the prior art. Other objects of the invention are to provide a process or membrane tank or a water treatment system or process.
• The present invention provides the advantage of a process or membrane tank with at least a collapsible portion. The tank may be manufactured from a flexible material and the entire tank may be collapsible.
• In one aspect, the invention provides an apparatus having a tank having at least a portion of its surface collapsible such that the tank can be configured in either a deployed position or a smaller stored position. A membrane module is located in the tank. The tank has a feed inlet and a permeate port in communication with the membrane module. When in the deployed position, water enters the inlet and flows through the membrane and out the permeate port in a filtration process. When filtration is no longer required, the tank can be collapsed for transport. The membrane module may remain in the tank when the tank is collapsed. For example, the membrane module may comprise hollow fiber membranes which may be rolled or folded with the tank. The ends of the membrane module may be held in the tank by connectors that facilitate collapsing the tank with the membrane module inside. The tank may have a retentate outlet for feed and bleed filtration or for filtration according to cycles of dead end filtration and tank deconcentration. The apparatus may also include an aerator and vent to permit gas scouring the membrane module. The aerator may be at least partially integral with the tank.
BRIEF DESCRIPTION OF THE DRAWINGS
• In the accompanying drawings:
• FIG. 1A is a perspective view of a first embodiment of a process tank according to the present invention.
• FIG. 1B is an elevation view of the first embodiment.
• FIG. 2 is an exploded perspective view of a second embodiment of a process tank according to the present invention.
• FIG. 3 is an elevation of view of the second embodiment.
• FIG. 4 is an elevation view of a header according to the second embodiment.
• FIG. 5 is a partial exploded perspective view of the second embodiment showing the connection of a header to a support frame.
• FIG. 6 is a cross-sectional view of the header ofFIG. 4 showing an adaptor bracket for connecting a membrane to the header.
DETAILED DESCRIPTION OF THE INVENTION
• An apparatus according to the embodiments described herein is suitable for use in the reverse osmosis water purification system disclosed in U.S. Pat. No. 6,120,688 (the '688 Patent). Accordingly, the entire specification of the '688 Patent is included by reference herein. The tank of the present invention may be used to replace the membrane tank disclosed in the '688 Patent. Alternately, the invention may be used with other water treatment processes or systems.
• FIGS. 1A and 1B show a process ormembrane tank10 according to a first embodiment of the present invention. Thetank10 includes atank surface12. Thetank surface12 may be composed entirely or generally of a flexible material, such as urethane coated fabric. When filled with raw water, thetank surface12 forms a pillow shape, as shown inFIGS. 1A and 1B. Optionally, only a portion of thetank surface12 may be composed of a flexible or collapsible material, and the remainder of the tank surface may be composed of a rigid material.
• A rawwater feed inlet14, a rawwater discharge outlet16, apermeate port18, and anair inlet20 are all located on thetank surface12.Camlok fittings22 are provided on each of theabove ports14,16,18, and20 to facilitate connection to corresponding hoses or lines (for example as described in the '688 Patent).
• Continuing to refer toFIGS. 1A and 1B, amembrane module30 is located in theprocess tank10. The membrane module may include a plurality of hollow fiber membranes in the form of a rectangular bundle suspended between first andsecond headers34aand34b, respectively. The rectangular bundle may be between four and twelve layers of membranes deep, and in the range of several tens of membranes wide. The membranes may have an outside diameter of 0.4 mm to 4.0 mm. The length of the membranes may be between 400 mm and 1800 mm. The membranes may have an average pore size in the microfiltration or ultrafiltration range, for example between 0.003 microns and 10 microns or between 0.02 microns and 1 micron. The membrane module may be as described in US Patent Publication No 2002/0179517 A1 which is incorporated herein in its entirety by this reference to it.
• A permeate cavity or conduit (not shown) is provided in the interior of secondsolid body34b. The permeate conduit transports permeate from the interior of themembranes32 to permeateport18.
• Loop restraint anchors36 are connected to thetank surface12 at opposing ends of thetank10. Elastomericbungee element restraints38 are connected to theanchors36 at one end and toslots40 milled in theheaders34a,bat the other end to position themembrane module30 in thetank10.
• Continuing to refer toFIGS. 1A and 1B, awatertight zipper50 is provided in thetank surface12. Preferably, thezipper50 is located along the compression stress line of thetank surface12. Any suitable number oftension restraints52 are connected to thetank surface12 on either side of the zipper to reduce the tension force acting on thezipper50.
• Anaerator60 is located in thetank10. Theaerator60 is connected to theair inlet20. A number of grommet vents62 are located in theaerator60 to diffuse air or other gases supplied to theaerator60 throughair inlet20 into thetank10. Theaerator60 may be composed of the same flexible material as thetank surface12.
• Aflush gas vent100 is provided in thetank surface12 to permit gas introduced through theaerator membrane60 to be released from thetank10. Thegas vent100 may be or operate as a one way valve allowing gas to escape, but not enter, thetank10.
• The operation of theprocess tank10 according to the first embodiment will now be described with reference toFIGS. 1A and 1B. The flexible material of thetank surface12 permits thetank10 to be collapsed to allow thetank10 and other components of a water treatment system (for example a feed pump or hose, a permeate pump or siphon hose, an air pump if desired, and valves or control devices if desired) to be transported to a desired location by a vehicle, such as a HUMWV. At the desired location, the system (not shown) is assembled and connected to a source of raw water. Feed flow to thetank10 may be by gravity or pump. Permeate may be drawn from themembrane module30 by pump, gravity flow or siphon. Air for air scouring may be provided by air pump or blower if desired from time to time, continuously, intermittently or during or near relaxation, backwashing or deconcentration processes. Permeation may be by dead end filtration, feed and bleed filtration, or cycles of dead end filtration and deconcentration. Backwashing may be performed, if desired, by elevating a permeate tank to above thetank10 or by pump from a permeate tank to permeateport18. Control may be by automatic or manual valves, turning pumps on or off, or altering the relative elevation of one or more of a feed tank, thetank10 or a permeate tank.
• In one process, the raw water enters thetank10 by pump or gravity from a flow source of surface or well water via thefeed inlet14 and fills the tank. When filled with raw water, thetank surface12 expands to the deployed position and assumes the pillow shape.
• A suction may be applied to permeateport18, for example by pump or siphon, to draw the water into the interior ofmembranes32, in order to filter, for example microfilter or ultrafilter, the water. The permeate travels from the interior of themembranes32 into the conduit insecond header34b, and intopermeate port18. Excess raw water may be discharged fromdischarge outlet16 back into the raw water source, to the ground or for irrigation use.
• Air from an air source (not shown), such as an air blower, may be diffused into thetank10 from grommet vents62 ofaerator60. The air may directly scrub themembranes32 or operate to induce movement to water contacting the outside ofmembranes32 to effect cleaning of themembranes32. Depending on themembranes32 used, movement may be induced to themembranes32. In other words, percolation of the air may cause themembranes32 to sway or move in thetank10, thereby effectively cleaning themembranes32.
• Flow of retentate throughdischarge outlet16 may be controlled by sizing or valving thedischarge outlet16 to give a feed and bleed flow of0 to 10% of the feed flow or to provide no bleed flow during some periods of time but drain at least a portion of thetank10 rapidly from time to time to deconcentrate it. Thegas vent100 may have a restricted opening size so as to trap a cushion of gas under thegas vent100 such that water will not escape thetank10 even if feed or intank10 pressure temporarily or continuously exceeds the static head in thetank10. However, thetank10 is not intended to be pressurized to a large degree, for example not more than 50% over ambient pressure.
• FIG. 2 shows a second embodiment of the present invention where asupport frame100 is provided to give the tank surface12 a predetermined shape. The predetermined shape may be a box-like shape where thetank surface12 includes atank lid flap101 which may be integral with the rest of thetank10. Like parts in this second embodiment will be assigned the same reference numbers as the corresponding parts in the first embodiment, and will not be further described.
• Referring toFIG. 2, thesupport frame100 consists of a number ofinterconnectable support members102 which are assembled into thesupport frame100. When thetank10 is in the stored position, thesupport members102 may be disassembled and stored in a more compact fashion. Preferably, the support members are 6061-T6 aluminum tubes having an outside diameter of 1″. Some of thesupport members102 may include conventionalmale connections104 and others may includefemale connections106 to secure thesupport members102 to each other by an interference fit.
• Discharge hose support108 and feedhose support110 may be provided onend pieces112a,112b,respectively, ofsupport members102.
• Support straps114 are preferably connected to the exterior oftank surface12 to attach thesupport frame100 to the exterior of thetank surface12.
• Continuing to refer toFIG. 2, anintegral aerator116 is provided in abottom portion118 in thetank surface12. Theaerator116 is connected toair inlet20.
• Referring toFIGS. 3-6, thesolid bodies34a,bare preferably connected to stainless steelsupport bracket assemblies35 which includeinverted channel sections200a,200b.Thesolid bodies34a,bare supported onsupport frame100 by theinverted channel sections200a,bwhich engage thesupport frame100. WhileFIGS. 3-6 show only onebracket assembly35, the other is supported on thesupport frame100 in an identical fashion.
• Referring now toFIGS. 2 and 6, each end of themembrane32 is connected throughsolid bodies34a,btobracket assemblies35 by anadapter bracket202. Thisadapter bracket202 slides into a slot (not shown) located in thesolid bodies34a,band is connected to thesolid bodies34a,bfor example by conventional screws, nuts, and washers.
• The operation of the second embodiment of theprocess tank10 according to the present invention will now be described.
• Thetank10 is transported to the desired location in the collapsed position. In other words, theflexible tank surface12 is collapsed or folded and thesupport frame100 is disassembled into theindividual support members102. During transport, azipper50 between thelid101 and the remainder of thetank10 is preferably closed to maintain an airtight seal between thetank flap lid101 and thetank100 in order to provide a moist environment which is desirable for themembrane32.
• Upon arrival at the desired location, thesupport frame100 is assembled at the desired location by connecting themale connections104 tofemale connection106 of thevarious support members102.
• Thetank10 is positioned within thesupport frame100, and secured by the support straps114. In this manner, thesupport frame100 forms an external support structure for thetank100. Thezipper50 is opened to provide access to the interior of thetank10. Theheaders34a,bare connected to thebracket assemblies35 and placed on thesupport frame100 as described above.
• Thetank10 is filled up with water as described for the first embodiment above. Thesupport frame100 causes thetank10 to assume the box-like shape when filled with raw water. Themembrane32 is suspended above the bottom of thetank10 and below the surface of the raw water. Thetank lid flap101 remains either fully or partially open during operation to permit air introduced into thetank10 by theaerator membrane116 to vent. In other respects, theprocess tank10 operates as described for the first embodiment above.
• While the present invention as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and thus, is representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims.

Claims (20)

1. An apparatus for a water treatment system comprising:

a) a tank having a tank surface, wherein at least a portion of the tank surface is collapsible between a deployed position adapted to store raw water, and a stored position wherein the portion is collapsed and the tank has a volume smaller than the deployed position;

b) a feed inlet located in the tank surface for receiving raw water;

c) a membrane module located in the tank; and,

d) a permeate port located in the tank surface, the permeate port being in fluid communication with the membrane module.

2. The apparatus ofclaim 1, wherein the portion is composed of a flexible material.

3. The apparatus ofclaim 1, wherein the tank surface is composed of the flexible material.

4. The apparatus ofclaim 3, further comprising a removable support frame, the tank surface being adapted to connect to the support frame to form the tank surface into a predetermined shape when in the deployed position.

5. The apparatus ofclaim 4, wherein the support frame comprises a plurality of interconnectable support members, the support members being adapted for compact storage when the tank surface is in the stored position.

6. The apparatus ofclaim 5, wherein the predetermined shape is a box like shape.

7. The apparatus ofclaim 6, wherein the support frame is located exteriorly of the tank surface when in the deployed position.

8. The apparatus ofclaim 1 further comprising an aerator and a gas port in communication with the aerator.

9. The apparatus ofclaim 1 wherein the membrane module comprises first and second solid bodies and a plurality of hollow fiber membranes extending between the solid bodies.

10. The apparatus ofclaim 9 having connectors between the solid bodies and the tank.

11. The apparatus ofclaim 1 wherein the portion is collapsible by rolling.

12. The apparatus ofclaim 9 wherein the portion is collapsible by rolling about one of the solid bodies.

13. The apparatus ofclaim 8 wherein a portion of the tank surface functions as a part of the aerator.

14. The apparatus ofclaim 9 having an aerator with holes located between the first and second solid bodies.

15. The apparatus ofclaim 1 wherein the tank surface comprises one or more zippers.

16. The apparatus ofclaim 15 having a tension restraint to reduce tension on a zipper.

17. The apparatus ofclaim 10 wherein the connectors are elastomeric.

18. The apparatus ofclaim 1 wherein the tank has a pillow like shape in the deployed position.

19. The apparatus ofclaim 1 wherein the tank has a gas vent.

20. The apparatus ofclaim 1 having a discharge outlet.

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